Cops have arrested a man for stabbing a woman to death in her Manhattan apartment Saturday.

Alexander Felix, 34, allegedly attacked his girlfriend Eloise Liz, 48, in her apartment on West 153rd Street after a heated argument about her adult son, according to police sources.

Neighbors told the Post they heard loud fighting in the wee hours of the morning, but by the time anyone called 911 it was too late for Liz.

Emergency responders found her around 4 a.m. that morning with multiple stab wounds to the chest, and pronounced dead at the scene.

Felix, who lives in East New York, was nabbed at a hospital while seeking medical attention for a cut on his own hand allegedly sustained during the attack, according to police. He is charged with second-degree murder and burglary.

Liz’ apartment building was rocked by tragedy two months ago, when a mother and her four-year-old son were allegedly killed by the child’s dad in a separate incident.